This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 50 |
| 2 | 1225 |
| 3 | 19600 |
| 4 | 230300 |
| 5 | 2118760 |
| 6 | 15890700 |
| 7 | 99884400 |
| 8 | 536878650 |
| 9 | 2505433700 |
| 10 | 10272278170 |
| 11 | 37353738800 |
| 12 | 121399651100 |
| 13 | 354860518600 |
| 14 | 937845656300 |
| 15 | 2250829575120 |
| 16 | 4923689695575 |
| 17 | 9847379391150 |
| 18 | 18053528883775 |
| 19 | 30405943383200 |
| 20 | 47129212243960 |